_spf.bigcommerce.com has no NS records.
NS records for this zone are defined at bigcommerce.com.
NS records for this zone are defined at bigcommerce.com.
Question and response
Question
dig _spf.bigcommerce.com. NS
Answer
The response has no answer records.
Authority
bigcommerce.com. 3600 SOA dns1.p04.nsone.net. hostmaster.nsone.net. 1648762509 43200 7200 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0